perf probe: Fix unchecked usage of strncpy()
authorArnaldo Carvalho de Melo <acme@redhat.com>
Thu, 6 Dec 2018 14:50:08 +0000 (11:50 -0300)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Tue, 12 Feb 2019 18:47:11 +0000 (19:47 +0100)
commit19d4c0fd85acdd0e2fc0f4e218ffaec72c0b9d6d
tree598a27093c09315878a69d90b38689fc214bddb3
parentf5d5b54349125f4765b51153960676ea4d81b82b
perf probe: Fix unchecked usage of strncpy()

[ Upstream commit bef0b8970f27da5ca223e522a174d03e2587761d ]

The strncpy() function may leave the destination string buffer
unterminated, better use strlcpy() that we have a __weak fallback
implementation for systems without it.

In this case the 'target' buffer is coming from a list of build-ids that
are expected to have a len of at most (SBUILD_ID_SIZE - 1) chars, so
probably we're safe, but since we're using strncpy() here, use strlcpy()
instead to provide the intended safety checking without the using the
problematic strncpy() function.

This fixes this warning on an Alpine Linux Edge system with gcc 8.2:

  util/probe-file.c: In function 'probe_cache__open.isra.5':
  util/probe-file.c:427:3: error: 'strncpy' specified bound 41 equals destination size [-Werror=stringop-truncation]
     strncpy(sbuildid, target, SBUILD_ID_SIZE);
     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  cc1: all warnings being treated as errors

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Fixes: 1f3736c9c833 ("perf probe: Show all cached probes")
Link: https://lkml.kernel.org/n/tip-l7n8ggc9kl38qtdlouke5yp5@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
tools/perf/util/probe-file.c